/Engine/Source/Runtime/Landscape/Classes/Landscape.h
Include Components with overlapped vertices X2/Y2 Coordinates are "inclusive" max values
static void CalcComponentIndicesOverlap ( const int32 X1, const int32 Y1, const int32 X2, const int32 Y2, const int32 ComponentSizeQuads, int32 & ComponentIndexX1, int32 & ComponentIndexY1, int32 & ComponentIndexX2, int32 & ComponentIndexY2 )